Soul Calibur

Bonus characters and stages:
Successfully complete the game with each of the standard characters to unlock a new character or stage. The final character to be unlocked is Edge Master.

Metallic characters:
Begin game play in mission battle mode and fight until the "Metal Mode" option is unlocked. Then, hold R while selecting a fighter.

Alternate costumes:
Press Y while choosing a fighter at the character selection screen.

Alternate title screen:
Successfully complete all missions in mission battle mode for a golden title screen. Unlock Inferno and all 338 pictures in the Art Gallery for a monochrome title screen.

Alternate underwear color for Sophitia: 
Highlight Sophitia and continuously press one of the following buttons or combinations at the character selection screen until she performs her pre-battle pose:
X
Y
B
X + B
X + Y
Y + B
X + Y + B

Mission battle bonuses:
Successfully complete all the missions to unlock the hidden art in the museum and a third costume for Sophitia, Voldo, Siegfried, Maxi, and Xianghua by pressing Y + A while selecting one of those characters. Completing all mission battles will unlock various museum options such as exhibition theater, opening direction (change the introduction), and character profiles. An "Extra Survival" mode will also be unlocked at the main screen.

Extra weapons:
Unlock Edge Master and successfully complete all mission battles. Hold L when selecting a fighter on the character selection screen for extra weapons.

Fight as Inferno:
Unlock all the characters, stages, and extra bonuses that are awarded by playing the game in arcade mode and mission mode. Get every picture in the mission mode. When this is accomplished, return to the arcade mode, and select Xianghua and her third outfit by pressing Y + A. If desired, the game may be set to one round and the easy difficulty. Play through and complete the game with her. After the credits complete, a new soul (Inferno) will appear to the right of Edge Master. He randomly switches weapons like Edge Master, but has some moves of his own that can be done with any weapon.

Change replay focus:
Normally, the replay camera will focus on the winner of the match. Press B to change the focus to the losing character.

Select victory pose:
Win a match, then press X, Y, or B during the replay to select one of the victory poses.

Arcade mode (Japanese version):
Successfully complete the game, including the bonus stages, with every character.

Fight as Unknown Soul (Japanese version): 
Unlock Edge Master. Then, hold R when selecting a fighter at the character selection screen to choose the "see through" Unknown Soul version.